Charging hopper for truck mixers



M. HENDERSON ET AL 2,489,885

cameme HOPPER FOR TRUCK mxnns Nov. 29, 1949 2 Sheets-Sheet 1 Filed June 4, 1947 R.M.HENDERSON 1.0mm EYCK INVENTOR.

Nov. 29, 1949 R. M. HENDERSON ET AL 2,439,385

CHARGING HOPPER FOR TRUCK MIXERS 2 Sheets-Sheet 2 Filed June 4, 1947 .HENDERSON .TEN EYCK IN V EN TOR.

' Patented Nov. 29, 1949 UNITED STATE PATENT oFnci:

CHARGING norrca roa TRUCK mxras poration of Delaware Application June 4, 1947, Serial No. 752,508

9 Claims. (01.259-161) This invention relates to concrete mixers and i more particularly to the operating mechanism and sealing means for the combined charging hopper and closure plate of truck mounted mixers.

In truck mixers, the mixing drum is rotatably mounted on the truck chassis and has an elevated, axial opening at the rear end through which material is charged and discharged. Spiral blading within the drum effects mixing when the drum is rotated in one direction and ejection of the material when it is rotated in the opposite direction. Associated with the opening is usually a funnel-like charging hopper which has a discharge end adapted to direct concrete making materials through the opening into the drum. A closure plate or door is attached to the discharge end of the hopper to close the opening during the charging and mixing operation and move with the hopper away from the opening to permit the discharge of the concrete. I

Since the mixing or agitating operation usually occurs while the truck is in motion, particular care must be taken to provide a sealing structure which will keep the fluid concrete from splashing or leaking out of the drum. For various reasons, it is preferred to have a charging hopper which does not rotate with the drum so that this sealing structure must also provide for relative rotation between the drum and the hopper. The sealing structures now employed in the art comprise in general, a fiat closure plate which is rotatably mounted on the hopper. When the drum opening is closed, the closure plate rotates with the drum and acts as a seal to prevent escape of concrete. According to the present invention, however, the closure plate is fixed to the hopper. Instead of the plate rotating, it engages a sealing ring which is mounted'on the end of the drum for relative rotation with respect to the drum. The sealing ring and door engage each other in a tapered joint which increases the contact area over that obtained with a fiat closure plate. By this construction the present invention arranges the parts consistently so that the'rotatable parts are mounted on the drum and the non-rotatable parts'are mounted onthe axially movable hopper., This arrangement improves the operation and increases the life of the sealing structure.

Two general types of construction are employed in the art for mounting the combined charging hopper and closure plate. In one, the hopper and plate are slidably mounted on a shaft supported by and'axially aligned within the drum. In the second, the hopper and plate are hinged or pivoted on a frame over the end of the drum. In the first construction there is a uniform engagement oi the periphery of the closure plate with.the mouth ,of the drum when the drum opening is closed. In the second construction,

f however, the plate and hopper, being pivoted to a frame, have an arcuate closing motion so that there is a non-uniform engagement of the periphcry of the plate with the drum during the closure operation. If the hopper and plate are hinged above the drum opening, the upper half of the closure plate will engagethe sealing ring before the lower half. Once it is realized that the closure plate or door is nothing more than a valve,

:0 Regardless of the foregoing analysis, however,

experience has shown that the second construction has two important advantages over the first. One advantage is that it has a greater rate of output. There are two reasons for this. In the first place the capacity of the drum of the first construction is decreased by the shaft mounted within the drum to support the closure plate. Secondly, the closure plate of the second construction is tilted with respect to the axis of the drum, due to its pivotal connection, during the discharge operation. As a consequence, the discharge opening between the drum and the plate is larger for thesecond construction than for the first and hence the rate of discharge is greater. The second advantage of the second construction is that after a period of operation it actually provides a better seal than the first. This is because in the first set-up the shaft on which the closure plate is mounted eventually deflects and throws the plate out of alignment with the drum opening unless it is made so large as to interfere with the charging and discharging operations.

The construction provided by the present invention hasall the desirable features and none of the undesirable features associated with the constructions just mentioned. In it the hopper and plate are mounted on the frame. However,

. they are not pivoted as in the second construction discussed above, but are slidably mounted on and supported by cam plates by means oi transverse arms on each side of the hopper. The cams control the path of traveler the hopper and plate. They are designed to cause movement which is coaxial with the drum axis when the plate is close to the mouth. of the drum and then tilting movement when the plate has moved beyond the region of incipient engagement with the drum. In this way the invention provides a closure plate which is uniformly seated around its periphery, in accordance with proper valve design, and which also has its travel positively controlled so that it is removed as effectively as possible from the path of concrete being discharged from the mouth of the drum.

In view of the fact that the frame, upon which the plate and hopper of the present invention are mounted, is a structure separate from that of the drum, it is likely that either elastic or permanent distortions will occur in the use of theinixer which will cause some misalignment of the closure plate with the mouth of the drum. Various features are therefore provided to compensate for such relative movements and insure effective sealing throughout the life of theunit. One such feature, of course, is the tapered sealing structure mentioned above. Other features and objects of the invention will appear in the detailed description of the accompanying drawings which show a charging hopper for truck mixers.

In the drawings:

Figure 1 is a side elevation, partly in section, of the invention and shows the hopper and plate in the fully closed position.

Figure 2 is a cross section through the sealing structure of the present invention.

Figure 3 is a view similar to Figure 1 but shows the hopper and plate in the tilted position for discharge of material from the drum.

Figure 4 is a detail view of the cam slot in the cam plate.

Figure 5 is a perspective view from the rear end of the mixing drum and shows the means for mounting and actuating the hopper and plate.

Figure 6 is an end view of the features shown in Figure 5.

The drawings show the elevated, materialtransfer and of a mixing drum I having an axial opening 2. The drum l is mounted for rotation in any suitable manner on the main frame (not shown) of the mixing machine. Circumjacent to the opening 2 is an annular flange 3. An annular bearing ring or guideway 4 is bolted to the flange 3 and, in effect, extends the length of the drum I so that discharge actually occurs through the opening 5 in the ring 4. The ring 4 has two outer flanges 6 and I and is attached to the drum flange 3 by means of the flange 6. The flange 1 is centrally positioned and serves as a bearing upon which the annular sealing ring 8 1s rotatably mounted.

The rings are recessed on each radial side of the, joint therebetween at the outer ends thereof to provide an annular recess 9. An annular gasket In of substantially the same width-is seated in the recess 9 and is forced snugly against the walls of the recess by means of the retainer H which is bolted to the ring 8. The gasket l0 thus effectively prevents ingress of concrete particles to the joint between the rings. (This particular feature as claimed in the copending application Number 609,071 of Henry Von Saspe, filed August 6, 1945, (now abandoned).) The ring 8 has a tapered annular lip l2 which guides the discharge flow of concrete and which engages theclosure plate. When the lip 2 engages the closure plate, it will not rotate due to the frictional forces therebetween. Ring 4 will continue to rotate, however, so that relative rotation 'the slots 2'") the The combined charging hopper and closure plate 20 consists of a dished closure plate 2| which is rigidly fixed to the usual funnel-like hopper 22 as shown at 23. There is an opening 2|a in the plate 2| so that material poured into the hopper 22 will flow directly into the drum I.

The hopper and closure plate 20 are supported on the cam plates 28 carried by the frame l3 for sliding movement toward or away from the opening 5. The hopper 22 has transverse arms or trunnions 24 on each side. The arms or trunnions 24 terminate in short cylindrical portions 25, which are in effect cam followers which rest upon the cam plates 28. U-shaped brackets 26 are mounted on the short cylindrical portions 25-outwardly of the cam plates. The followers 25 ride in cam slots 21 in the cam plates 28 and the cam plates are fixed to the upright members l4 and I5 so that the weight of the hopper and plate 20 is transmitted through the cam plates 28 to the frame l3.

The shape of the cam slots 21 determines the path of movement of the hopper and plate 20. Hence, it is possible to obtain any desired motion of the hopper and plate 20, within reasonable limits. The preferred slot shape is shown in Figure 4. It is apparent from this figure that the slot 21 consists of two separate portions 21a and 27b. In the construction shown the axes of the two slots 21a (on either side of the hopper) and the axis Of the drum opening 5 lie in the same plane. Consequently, when the hopper and plate 20 are moved along the path governed by the slots 21a, the axis of the plate 2| will be coaxial with the axis of the drum opening 5. This is proper valve motion and the dished periphery of the plate 2| will seat uniformly on the tapered lip |2 of the sealing ring 8.

The other portions 21b of the cam slots are not parallel to the axis of the opening 5 but are inclined at an obtuse angle to the aforementioned plane through the axis and the slots 21a. As shown in Figure 3, when the followers 25 are in hopper end plate 20 will be tilted so that the lower portion of the plate 2| is spaced further from the lip 2 than would occur with coaxial travel. This provides a maximum area of the effective opening between the plate 2| and the lip l2 and increases the rate of discharge over that obtained with a straight coaxial travel of the hopper and plate 20.

Those in the art will realize that there are many ways to move the hopper and plate 20 in the cam slots 21. It should be noted that the weight of the hopper and plate 20 will tend to force it to a closed position because of the cam slots 21. The operating mechanism should, therefore. be of the irreversible type to prevent undesired closing of the opening and for that reason it should be either a hydraulic system or a mechanical system having proper toggle action or a worm and wheel arrangement.

of the slope The form selected for illustration is of the worm and wheel type.

The immediate means for moving the hopper and plate 30 are the links 3|. The links are of QJIBOJOI of the brackets 23 and have shoulders 3i bearing against the inner legs to force the hopper and plate outwardly. Springs 32 on the links 30 provide a yieldable connection between the outer legs of the brackets 26 and the ends 33 of the links 30. When the opening is closed, force is transmitted through the springs to the outer legs. Since the links pass through the two bracket legs, they will prevent undesired twisting or tilting of the hopper and plate 20 which will therefore have positions determined by the cam slots 21. The springs 32 provide flexibility of the closure structure about a vertical axis. bility about a horizontal axis is secured simply by making the camslots 21 somewhat wider than the cam followers25.

The links are pivotally connected at their inner ends, as shown at 31, to the bottom ends of operating arms 35 which are fixedly connected at 36 to a horizontal rocker shaft 31 pivotally attached to the frame l3 above the opening 5. Rotation of the rocker shaft 31 will swing the arms 35 and thus cause longitudinal or axial movement of the links 30 and the hopper and plate 20. Since the links 30 are pivotally conthe linkage 4| which rotates the rocker shaft 3'I and thus moves the hopper and plate 20 as previously described.

The usual discharge chute 45 is provided and may be attached to the cam plates 28 and the uprights l4 and I5 as clearly shown in Figure 5.

The invention comprehends such modifications as fall within the scope of the appended claims.

What is claimed is:

1. In a concrete mixer having a mixing drum with a material-transfer port at one end and a frame near said port, the combination of a com. bined charging hopper and closure plate for said port, cam plates connected to said frame for supporting said hopper and plate and for controlling the path of movement thereof during opening and closing of said port, and means carried by said hopper and plate and slidably mounted on said cam plates, and operating mechanism connected to said means and to said frame for effecting opening and closing movements of said hopper and plate, said cam plates provided with hopper supporting and movement guiding surfaces, the initial portions of said guiding surfaces which are nearest to the drum extending in a plane substantially parallel with the longitudinal axis of said drum and the remaining portions of said surfaces extending upwardly at an obtuse angle to the initial portions of the surfaces whereby when movement of said hopper is initiated it will move bodily in a direction coaxial with the axis of the drum for a predetermined distance and thereafter will move at an obtuse angle to the axis of the drum 2. In a concrete mixer having a mixing drum with a material-transfer port at one end and a frame near said port, the combination of a combined charging hopper and closure plate for said Flexiport, cam plates connected to said frame for supporting said hopper and plate and for controlling the path of movement thereof during opening and closing of said port, and means carried by said hopper and plate and slidably mounted on said cam plates, and operating mechanism connected to said means and to said frame for effecting opening and closing movements of said hopper and plate, said operating mechanism having irreversible moving means to prevent closing movement of said combined hopper and plate due to the force of gravity, said cam plates provided with hopper supporting and movement guiding surfaces, the initial portions of said guiding surfaces which are nearest to the drum extending in a plane substantially parallel with the longitudinal axis of said drum and the remaining portions of said surfaces extending upwardly at an obtuse angle to the initial portions of the surfaces whereby when movement of said hopper is initiated it will move bodily in adirection coaxial with the axis of the drum for a predetermined distance and thereafter will move at an obtuse angle to the axis of the drum.

3. In a concrete mixer having a rotatable mixing drum with an end opening for material transfer purposes and a frame near said opening, a non-rotatable charging hopper attached to said frame, a closure plate rigidly fixed to said hop per, cam means attached to said frame for determining the path of opening and closing movement of said closure plate, and means for moving said hopper and plate along the path determined by said cam means, said cam means including hopper supporting and movement guiding surfaces having movement guides arranged whereby uponmovem'ent of the hopper it will initially move bodily coaxially with the axis of the drum and subsequently will move upwardly at an 0btuse angle to the axis of the drum.

4. In a concrete mixer having a rotatable mix! ing drum withan axial opening at one end for material transfer purposes and a frame strad dling said opening, a pair of cam plates attached to said frame, one on each side of said opening,

a charging hopper having its discharge and adapted to deliver concrete making materials through said opening, trunnions on said hopper resting upon said cam plates, said cam means including hopper movement guiding surfaces arranged whereby upon movement of the hopper it will initially move bodily'coaxially with the axis of the drum and subsequently will move upwardly at an obtuse angle to the axis of the drum, and means connected to said trunnions for moving said hopper.

5. In a concrete mixer having a rotatable mixing drum with an axial opening at one end for material transfer purposes and a frame straddling said opening, a pair of cam plates attached to said frame, one on each side of said opening, a charging hopper having its discharge end adapted to deliver concrete making materials through said opening, trunnions on said hopper resting upon said cam plates, said cam plates provided with hopper movement guiding surfaces, the initial portions of said guiding surfaces which are nearest the drum extending in a plane substantially parallel with the longitudinal axis of the drum and the remaining portions of said surfaces extending upwardly at an obtuse angle to the initial portions of the surfaces wherebywhen movement drum with an end opening chargingpurposesandaframe 7' move in a direction at anobtuseangletothe axis ofthe drum. and means connected to said trunsaid trunnions, floating links slidably engaging said cam follower means to transmit force thereto in a' plane substantially parallel to the axis of the drum, arms pivotally connected to said links and to the top of said frame, and means for rotating said arms about their pivotal connections at the top. of said frame to cause opening and closing movement of said hopper and plate. said cam means provided with hopper movement guiding surfaces, the initial portions of said guiding surfaces which are nearest the drum extending in a plane substantially parallel with the longitudinal axis of said drum and the remaining portions of said surfaces extending upwardly at an obtuse angle to the initial portions of the surfaces wherebywhen movement of said hopper is initiated it will move bodily in a direction coaxial with the axis of the drum for a predetermined distance and thereafter in a direction at an obtuse angle to the axis of the drum.

- 7. In a concrete mixer having a rotatable mixing drum with an axial opening at one end for material transfer purposes and a frame straddling said opening, a pair of cam plates attached to said frame, one on each side of said opening, a charginghopper having its discharge end adapted to deliver concrete making" materials through 'said opening, trunnions on said hopper resting upon said cam plates, cam follower means connected to said trunnions, floating links slidably engaging said cam follower means to transmit force thereto in a plane substantially Parallel to the axis of the drum, arms pivotally connected to said links and to the top of said frame, and means for rotating said arms about their pivotal connections at the topof said frameto cause opening and closing movement of said'hopper'and plate, said cam means provided with hopper movement guiding surfaces, the initial portions of said guiding surfaces which are nearest the drum e in a plane substantially parallel with the longitudinal axis of said drum and'the remaining portions of said surfaces extending upwardly at an obtuse angle to the initial portions of the surfaces whereby when movement of said hopper is initiated it will move bodily in a direction coaxial with the axis of the drum for a predetermined distance and thereafter in a direction at an obtuse angle to the axis of the drum, said hopper having an annular closure member about its discharge opening for sealingcontact with said drum and resilient pressure means connected to said cam follower means'for yieldably forcing said closure member into engagementrwith said drum.

8. In a truck mixer having a rotatable mixing near. said opening,

for and-dis- 3 i-Icing M, a closure plate for said opening rigidly fixed to said hopper, means connected to said frame for operating said combined chargguide and support plates, said guide and supportplates having hopper movement guiding surfaces thereon, the initial portions of said guiding surfaces which are nearest the drum extending in a plane substantially parallel with the longitudinal axis of the drum and the remaining portions of the surfaces extending upwardly at an obtuse angle to the initial portions of the surfaces whereby when movement of said hopper is initiated it will move bodily upon said surfaces in a direction coaxial with the axis of the drum for a. predetermined distance and thereafter in a direction at an obtuse angle to the axis of the drum.

9. In a ccncreteumixer having a drum with a port for charging and dischar ing p ses and a frame straddling said port, a combined charging hopper and closure plate for said port, transversely extending trunnions fixed to opposite sides of said hopper, each of said trunnions including a cam follower, a U-shaped bracket on each of said camfollowers, rods extending through said brackets having flanges for engaging one arm of each of saidb'rackets, resilient means connected to the outer ends of said rods and with the other arm of each of said brackets, cam means for said cam followers attached to said frame, actuating means attached to said frame for moving said rods so that the path of travel of said hopper and plate is determined by said cam means, said cam means provided with hopper supporting and movement guiding surfaces, the initial portions of said guiding surfaces which are nearest the drum extending in a plane substantially parallel with the longitudinal axis of the drum and the remaining portions of said surfaces extending upwardly at an obtuse angle to the initial portions of the surfaces whereby when movement of said hopper is initiated it will move bodily in a direction coaxial with the axis of the drum for a predetermined distance and thereafter in a. direction at an obtuse angle to the axis of the drum.

ROBERT M. HENDERSON. JOHN c. 'I'EN EYCK.

REFERENCES crrizn' UNITED STATES PATENTS Number Name Date 2,105,873 Weinheimer Jan. 18, 1938 2,223,307 Pacchetti et a1 Nov. 26, 1940 2,265,751 Ball Dec. 9, 1941 2,350,285 Haxon' May 30,1944 2,360,345 Elkemeier Oct. 17, 1944 2,374,912 Barnes May 1, 1945 2,398,549 Murphy Apr. 16, 1946 2,451,555 'Hilkemeier et al. Oct. 19, 1948 

